1. Field of the Invention
The present invention relates to a power converter, or more in particular to an improvement of a snubber circuit.
2. Description of the Prior Art
A power converter circuit capable of regeneration of snubber energy to a power supply with the operation of a switching element is proposed in JP-A-64-89972.
The circuit according to the above-mentioned is intended for regenerating snubber energy in an asymmetric circuit configured of different snubber capacitors engaged in switching of upper and lower semiconductor switching elements.
On the other hand, an asymmetric circuit of a series multiple inverter is disclosed in JP-A-1-198280.
In the above-mentioned prior art, a capacitive element is charged to more than a source voltage to regenerate a stored charge to a power supply by a snubber action at the time of switching operation of only one of the switching elements.
The prior art poses the problem that an asymmetric configuration increases the whole size of the apparatus.
A symmetric snubber circuit is disclosed in FIG. 11 on page 119 of an article entitled "GTO Driving and Protection Technique with Status Monitoring", p., IEEE Transactions on Industry Applications, Vol. 24, No. 1, January/February 1988, pp. 115-120.
No consideration is given, however, to a decreased size of the apparatus in the prior art.